1. Field of the Invention
The invention is directed to a method to beneficiate platinum and platinum group element ores contained in selected sediments (e.g., beach and alliuvium samples in the area near Good News Bay, Alaska) by magnetic separation.
2. Discussion of Prior Art
The recovery of by-product heavy minerals from gravel, various sediments and industrial mineral operations is of great commercial interest. For example, the Bureau of Mines has investigated such recovery as part of a continuing effort to maximize the recovery of minerals and metals within the United States. Heavy mineral concentrates (HMC), also referred to as black sands, were early investigated by the U.S. Geological Survey. Heavy minerals found, for example, in California black sands include magnetite, ilmenite, hematite, chromite, zircon, garnet, scheelite, cinnabar, gold and platinum-group metals (PGM). All of these minerals hve economic potential, however, few successful or commercially feasible means, except for gold, for recovering such minerals as by-products from sand and gravel operations have been discovered.
Beneficiation techniques such as gravity concentration and fractionation of heavy-mineral concentrates are known techniques. See for example, Report of Investigations 8366, Recovering By-Product Heavy Minerals from Sand and Gravel, Placer Gold, and Industrial Mineral Operations by J. M. Gomes, G. M. Martinez, and M. M. Wong, [Washington]: United States Department of the Interior, Bureau of Mines, 1979.
The use of conventional magnetic separators to remove ferromagnetic minerals is known. Magnetic separation is an important process that has been used in mineral dressing for many years. Most metallic ores are crushed and the values are concentrated using flotation, gravity settling, electrostatic separation, or other special processes. Test work conducted on several metallic ores using a wet magnetic mineral separator has been reported. John B. Mertie, Jr., U.S. Geological Survey Prof. Paper 938 (1976) disclosed an analytical process wherein magnetite was removed from various minerals without the inclusion of other minerals. However, no work has been reported using new high intensity, high gradient magnetic separators on metallic ores. The method disclosed herein to isolate paramagnetic fractions contained in various sediments to beneficiate platinum group element ores therein is, therefore, believed to be novel.